C#一些时间处理方法

╰+哭是因爲堅強的太久メ 2021-09-15 12:50 309阅读 0赞

1、字符串日期转DateTime型

2、获取本年的第几周

3、获取指定周的日期范围（开始时间：周一；结束时间：周日）

4、获取今天是星期几

**1、字符串日期转DateTime型**

/// <summary>  
    ///  字符串日期转DateTime  
    /// </summary>  
    public static DateTime TransStrToDateTime(string strDateTime)
    {
        DateTime now;
        string[] format = new string[]   
        {   
            "yyyyMMddHHmmss", "yyyy-MM-dd HH:mm:ss", "yyyy年MM月dd日 HH时mm分ss秒",  
            "yyyyMdHHmmss","yyyy年M月d日 H时mm分ss秒", "yyyy.M.d H:mm:ss", "yyyy.MM.dd HH:mm:ss","yyyy-MM-dd","yyyyMMdd"  
            ,"yyyy/MM/dd","yyyy/M/d"  
        };
        if (DateTime.TryParseExact(strDateTime, format, CultureInfo.InvariantCulture, DateTimeStyles.None, out now))
        {
            return now;
        }
        return DateTime.MinValue;
    }
    
    /// <summary>  
    ///  字符串日期转DateTime?  
    /// </summary>  
    public static DateTime? TransStrToDateTimeNull(string strDateTime)
    {
        DateTime? result = null;
        if (String.IsNullOrEmpty(strDateTime))
        {
            return null;
        }
    
        string[] format = new string[]   
        {   
            "yyyyMMddHHmmss", "yyyy-MM-dd HH:mm:ss", "yyyy年MM月dd日 HH时mm分ss秒",  
            "yyyyMdHHmmss","yyyy年M月d日 H时mm分ss秒", "yyyy.M.d H:mm:ss", "yyyy.MM.dd HH:mm:ss","yyyy-MM-dd","yyyy-MM","yyyyMMdd"  
            ,"yyyy/MM/dd","yyyy/M/d","yyyy-MM-ddTHH:mm:ss","M/d/yyyy","MM/dd/yyyy"
        };
        DateTime now;
        if (DateTime.TryParseExact(strDateTime, format, CultureInfo.InvariantCulture, DateTimeStyles.None, out now))
        {
            result = now;
        }
        return result;
    }

**2、获取本年的第几周**

**3、获取指定周的日期范围（开始时间：周一；结束时间：周日）**

/// <summary>
    /// 获取本年的第几周
    /// </summary>
    public static int GetWeekOfYear(DateTime dateTime)
    {
        GregorianCalendar gc = new GregorianCalendar();
        int weekOfYear = gc.GetWeekOfYear(dateTime, CalendarWeekRule.FirstDay, DayOfWeek.Monday);
        return weekOfYear;
    }
    
    /// <summary>
    /// 获取指定周的日期范围（开始时间：周一；结束时间：周日）
    /// </summary>
    /// <returns>数组0：开始时间；数组1：结束时间</returns>
    public static DateTime[] CalcWeekDay(DateTime dateTime)
    {
        DateTime[] result = new DateTime[2];
    
        int year = dateTime.Year;
        int week = GetWeekOfYear(dateTime);
    
        DateTime first = DateTime.MinValue;
        DateTime last = DateTime.MinValue;
    
        //指定年范围  
        DateTime start = new DateTime(year, 1, 1);
        int startWeekDay = (int)start.DayOfWeek;
        //周的起始日期  
        first = start.AddDays((8 - startWeekDay) + (week - 2) * 7);
        last = first.AddDays(6).AddHours(23).AddMinutes(59).AddSeconds(59);
    
        result[0] = first;
        result[1] = last;
    
        return result;
    }

**4、获取今天是星期几**

/// <summary>
    /// 获取今天是星期几
    /// </summary>
    public static int GetWeek()
    {
        int[] Day = new int[] { 7, 1, 2, 3, 4, 5, 6 };
        int week = Day[Convert.ToInt32(DateTime.Now.DayOfWeek.ToString("d"))];
        return week;
    }